A while ago I was writing a sequence of articles — interrupted for some weeks by all the hullabaloo over Higgs particles and all the noise about neutrinos — concerning the possibility that the world has more than the three spatial dimensions that are obvious to us. These “extra” dimensions seem to be very confusing to non-experts, so I’ve been trying to find a way to make them seem a little less strange. We’ll see if I’ve succeeded. Building on my articles describing some types of worlds of 1 spatial dimension and of 2 spatial dimensions, I’ve now written an article giving one type of example of an “extra” dimension. Other articles to follow over coming weeks will provide other examples of extra dimensions, as well as an attempt to explain how scientists can potentially look for evidence of an extra dimension.